Painting systems use known rotary atomizers, which have a so-called bell-shaped plate that is driven by a compressed-air turbine at high rpm. The bell-shaped plate is usually shaped like a truncated cone and expands in the direction of spraying, with the coating agent to be applied being accelerated in the truncated cone-like bell-shaped plate due to centrifugal forces in the axial direction and particularly in the radial direction, so that a conical spray stream is produced at the stub edge of the bell-shaped plate.
Furthermore, to form the spray stream it is known to blow so-called steering air onto the outer surface of the bell-shaped plate, with the steering air influencing the direction of the paint particles sprayed at the stub edge of the bell-shaped plate. By controlling the amount and the speed of the blown steering air, the shape of the spray stream, and thus the spray stream width, can be adjusted.
It is further known from DE 102 02 712 to direct two steering air streams, which can be controlled separately from each other, onto the spray stream.
For the known rotary atomizers of the previously described type, the steering air is supplied by a steering air line, which runs within the housing of the rotary atomizer towards the outside, between the housing wall and the compressed air turbine. In contrast, the steering air line meets an inlet in the mounting-side end surface of the rotary atomizer, the position of which is predetermined by corresponding connections in the attachment flange of the associated coating machine, such as, e.g., a painting robot, and thus cannot be changed.
A first disadvantage of the previously described guidance of the steering air line within the rotary atomizer, towards the outside between the housing wall and the compressed air turbine, is the fact that the housing diameter of the rotary atomizer is increased by the required cross section of the steering air line, with the installation space available for the compressed air turbine being reduced by the steering air line.
Another disadvantage of the known arrangement of the steering air line is that the steering air line must be first redirected, starting from the connection in the mounting-side end surface, in order to be able to guide it past the compressed air turbine on the outside. This guidance of the steering air line is poor in terms of flow dynamics, however, because the flow resistance is increased by the changes in direction of the steering air and undesired resonance effects can also appear within the steering air line, which produce worse painting results.
The invention is therefore based on the problem of optimizing the known rotary atomizer, described in the introduction, with reference to the required installation space and in terms of the flow dynamics.